IDSA Guidelines for Enterobacter Infections
Carbapenems (imipenem-cilastatin, meropenem, doripenem) are the first-line agents for treating Enterobacter infections due to the high risk of resistance to other antimicrobials, particularly cephalosporins. 1
Antimicrobial Recommendations
First-line Therapy
- Carbapenems (imipenem-cilastatin, meropenem, doripenem) are the preferred agents for Enterobacter infections due to their stability against AmpC β-lactamases commonly produced by Enterobacter species 1
- Fourth-generation cephalosporins (cefepime) may be used if Extended-Spectrum Beta-Lactamase (ESBL) production is absent 1, 2
Alternative Therapies
- Piperacillin-tazobactam can be considered as an alternative, though with caution due to potential resistance 1
- Fluoroquinolones (ciprofloxacin, levofloxacin) combined with metronidazole may be used in areas with low fluoroquinolone resistance rates (<20%) 1
Resistant Enterobacter Infections
- For carbapenem-resistant Enterobacter infections, options include 1:
- Polymyxins (colistin)
- Tigecycline
- Fosfomycin
- Double carbapenem regimen (in selected cases)
Important Considerations
Cephalosporin Resistance
- First and second-generation cephalosporins are generally ineffective against Enterobacter infections 1
- Third-generation cephalosporins are not recommended due to the high likelihood of resistance development during therapy, particularly for Enterobacter cloacae and Enterobacter aerogenes 1, 3
- Enterobacter species can develop resistance to cephalosporins during treatment through induction of AmpC β-lactamases 4, 3
Healthcare-Associated vs. Community-Acquired Infections
- For healthcare-associated Enterobacter infections, broader empiric coverage is recommended due to higher resistance rates 1
- For community-acquired infections in areas with low resistance rates, more targeted therapy may be appropriate 1
Special Populations
- For critically ill patients with Enterobacter infections, combination therapy may be initially considered until susceptibility results are available 1
- Immunocompromised patients may require broader empiric coverage 1
Treatment Duration and Monitoring
- For bacteremia and most infections, 7-14 days of appropriate therapy is typically sufficient 1
- Longer courses may be needed for complicated infections, endovascular infections, or in immunocompromised hosts 1
- Broad-spectrum antimicrobial therapy should be tailored when culture and susceptibility reports become available to reduce the number and spectra of administered agents 1
Regional Considerations
- Local resistance patterns should guide empiric therapy choices, particularly regarding fluoroquinolone use 1
- In regions with high rates of ESBL-producing or fluoroquinolone-resistant Enterobacteriaceae (>20%), fluoroquinolones should be avoided for empiric therapy 1
Remember that Enterobacter species can rapidly develop resistance during treatment, particularly with cephalosporins, making carbapenems the safest empiric choice for serious infections until susceptibility results are available 4, 3.